DCI bios support

dpizzito

Hey Guys,

Trying to enable DCI(direct connect interface for intel debug) support in the UP Board bios, and I didn't see it anywhere in the options(usually it is in the advanced CPU settings). This is the 2016 bios. Unfortunately, had a snafu with the update to the 2018 bios(covered in another post), so I didn't get to see if it was an option in the latest and greatest either. I believe the up squared 2018 bios has the DCI option included. Does the 2018 bios for the regular up board have this option?

It also just occurred to me that you enter the bios by default as user, not admin without entering the admin password. Are the DCI settings hidden in the admin login? Even in the 2016 version?

Thanks

Edit: fixed formatting (please don't insert spaces before paragraphs)

eduncan911

For the UP Squared, I have BIOS 3.3 on mine and I can't find an option for DCI myself. Do you know where it is located on the UP^2?

I also updated my UP Board today to the 2018 bios that you used in other post: I went through all of the settings; however, I did not see any DCI options either.

dpizzito

Not sure, I was just going by this item in the list of improvements in the v3.3 bios (https://downloads.up-community.org/download/up-squared-uefi-bios-v3-3/) :

Intel Request: Support Apollo Lake DCI Debug Interface

Did you try the admin password to unlock the advanced features? Maybe the DCI setting is in there.

Thanks again,
-Dylan

eduncan911

@dpizzito said:
Not sure, I was just going by this item in the list of improvements in the v3.3 bios (https://downloads.up-community.org/download/up-squared-uefi-bios-v3-3/) :

Intel Request: Support Apollo Lake DCI Debug Interface

Did you try the admin password to unlock the advanced features? Maybe the DCI setting is in there.

Thanks again,
-Dylan

Well, it is a different chipset between the two boards. The ApolloLake really is a much more advanced chipset IMO.

And per this link, it sounds like it is only for the newer Atom CPUs on the ApolloLake chipset - not older Atoms like on the CherryTrail chipset in the UP Board (also see the comments at the bottom):

https://software.intel.com/en-us/articles/system-debugging-via-direct-connect-interfacedci-of-intel-system-debug

And no, I don't use the admin passwords. Already lost one board to advanced settings. Won't do that again.

dpizzito

Thanks for looking into it more,

Just checked the datasheet(https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/atom-z8000-datasheet-vol-1.pdf) for the z8000 series(cherry trail aka cherry view), and on page 22 it indicates that it does support DCI over USB via the USB DCI controller.

So I think the functionality is there, it comes down to BIOS support. I also believe that there is no other way to do hardware level debugging on the up board without DCI, although I'll do more research on that.

-Dylan

dpizzito

Boards finally came in, got the time to look at the engineering(admin) bios settings.... No DCI Enable option anywhere.

So, I think I will have to write to the DCI register during normal operation, a good example can be found here:
https://embedi.com/blog/uefi-bios-holes-so-much-magic-dont-come-inside/

Part 2 of the Cherry View SOC datasheet has the register address for this BTW, then you just need to write to it using devmem2.

If the BIOS is already locking writes to this register via the lock bit, then this will not work either. Will then have to consider modifying the BIOS itself, the above link goes a little into more detail on that as well. Could very well be that the BIOS does have a enable dci setting that is not visible to the user. It does seem like just a simple register write that the bios needs to include though, nothing more.

Either that, or the latest BIOS I tried to install on the board I bricked does have this feature, too scared now though to try to flash another up board with the latest bios and brick another one.

On a side note, as I was perusing the admin settings, I was wondering to myself: how can one of these boards be permanently bricked if removing the CMOS battery wipes out any bad settings?